1. Field of the Invention
The invention in general relates to radar or sonar systems, and more particularly, to a system for forming an extremely narrow receiver beam.
2. Background Information
In radar or sonar systems, electromagnetic or acoustic energy, as the case may be, is transmitted toward a target area. Reflected energy from a target in the area is detected by a receiver array comprised of a plurality of receiver elements, the corresponding output signals of which are processed to provide a target signal.
The response of the array varies with the direction of incoming energy relative to the array, such response being defined by a beam pattern having a predetermined beam width.
The resolution of the system is determined by the beam width and it is generally desirable to be able to resolve small and closely spaced objects. Finer resolution, that is, narrowing the beam width, is typically achieved by increasing the receiver array aperture. However, since increased aperture is generally achieved only through increased platform size, and additional receiver elements with associated electronics, it is not a cost effective option for systems which are size and power limited. The present invention provides for a system which significantly improves resolution without increasing aperture size and is applicable for both radar and sonar applications.